For example, related technology of initiating and controlling a mail function of a telephone device is disclosed at paragraphs [0021] to [0023] and FIGS. 1 and 6 of Japanese laid-open patent publication No. 2004-363925 (hereinafter referred to as Patent Literature 1).
Patent Literature 1 discloses:                Determining whether a receiving party has responded to a telephone call within a predetermined period of time;        Determining whether the receiving party is one of specific parties (users registered in an address book) if the receiving party did not respond within the predetermined period of time; and        Automatically initiating a mail function when the receiving party did not respond within the predetermined period of time and is one of the specific parties.        